Methodology comparison, 2026
Black-Box vs White-Box vs Grey-Box Pentest Cost (2026)
The choice between black-box, grey-box, and white-box methodology has a direct effect on cost and on findings yield. Black-box is the cost baseline. Grey-box adds 20-40% but produces 15-30% more high-impact findings. White-box adds 60-80% and is justified only for the most security-sensitive scopes. This page covers the cost mechanics, findings-yield analysis from real engagements, and a decision framework for choosing the right methodology for your scope.
Black-box
Base cost
No source code, dynamic only
Grey-box
+20% - +40%
Selective source review
White-box
+60% - +80%
Full code + threat model
Cost mechanics by methodology
The cost difference between methodologies traces directly to the number of consultant days required for each. Black-box is purely dynamic: the tester probes the running application from outside with documented credentials. Grey-box adds source code review time for selected components (typically authentication, authorisation, and any cryptographic primitives). White-box adds a comprehensive code review pass over the entire application surface plus threat-model validation.
| Methodology | Days for mid-sized SaaS app | Cost (boutique) | Cost vs black-box |
|---|---|---|---|
| Black-box (dynamic only) | 5-7 testing days | $10,000 - $14,000 | Baseline |
| Grey-box (auth + authz code review) | 7-10 testing days | $13,000 - $19,000 | +25-35% |
| White-box (full code review + threat model) | 10-15 testing days | $18,000 - $27,000 | +70-90% |
Findings yield comparison
The most useful way to think about methodology choice is findings-per-dollar rather than just findings count. The table below summarises the typical findings outcome we observe across the buyer corpus for identical mid-sized SaaS application scopes.
| Methodology | Critical findings (avg) | High findings (avg) | Total findings (avg) | Critical+High per $1K |
|---|---|---|---|---|
| Black-box | 0.4 | 2.1 | 12 | 0.21 |
| Grey-box | 0.7 | 3.0 | 16 | 0.23 |
| White-box | 0.9 | 3.8 | 23 | 0.21 |
Aggregated across mid-sized SaaS engagements 2024-2026. Each engagement scoped to roughly the same application surface. Estimated averages, not statistical claims.
When black-box wins
Black-box is the right methodology for three classes of scope. The first is compliance-evidence pentests where the auditor's expectation is "an independent assessor failed to break in from outside". SOC 2 Type II annual evidence usually fits here. The second is acquired-company applications where source code access is genuinely impractical or contractually blocked. The third is product-due-diligence pentests where you want a buyer-style adversarial perspective and explicitly do not want the tester biased by source code visibility.
Black-box is also the right floor methodology for any first-time pentest. If your application has never been tested, black-box will surface enough surface-level issues to be valuable, and you can move to grey-box on subsequent engagements once the obvious flaws are fixed.
When grey-box wins
Grey-box is the best methodology for most modern web and API applications. The marginal cost over black-box is modest (20-40%) and the marginal findings yield is meaningful (15-30% more high-impact issues). Grey-box catches business-logic flaws, authorisation gaps, and cryptographic mistakes that black-box rarely reaches because the tester would need to spend days enumerating attack surface that source code reveals in minutes.
Grey-box scope typically gives the tester source access to authentication and authorisation code, cryptographic primitives, and any complex business-logic workflows the customer flags as security-relevant. The tester does not read the entire codebase; they spot-check specific components while doing dynamic testing in parallel.
For PCI DSS pentests, FedRAMP testing, and any application handling financial or healthcare data, grey-box is increasingly the expected default. Auditors recognise that black-box on a payment system is leaving findings on the table.
When white-box wins
White-box is justified for the most security-sensitive components where a single missed flaw could produce material harm. Specific examples include cryptographic implementations (libraries that perform their own key derivation, signing, or encryption rather than calling vetted primitives), identity providers (custom OAuth or SAML servers, federation bridges), financial transaction engines (any system that moves money or settles trades), and healthcare data processing (any system handling PHI where regulatory exposure is acute).
For general-purpose SaaS applications, white-box is rarely the right choice. The 60-80% premium over black-box does not pay back in additional findings of equivalent severity, and the time spent on comprehensive code review is better invested in periodic grey-box engagements at a higher cadence.
The most common buyer mistake
The most consistent buyer mistake we see is choosing black-box because it is the cheapest option, when the application scope clearly warrants grey-box. The marginal cost difference (typically $3,000-$6,000 on a mid-sized application engagement) is small relative to the additional findings yield, but buyers anchor on the cheaper number when comparing quotes.
A useful framing is: if the application handles authentication, authorisation, payment, or sensitive personal data, grey-box is almost always the right buy. Black-box on these scopes is leaving high-impact findings undetected to save what is, in dollar terms, a single day of consultant time.
Frequently asked questions
What is the cost difference between black-box, grey-box, and white-box pentests?v
Black-box is the cheapest methodology and serves as the cost baseline. Grey-box adds approximately 20-40% to the engagement cost because the tester reviews source code for selected components in addition to dynamic testing. White-box is the most expensive at typically 60-80% above black-box because the full source code, threat models, and architecture documentation must all be reviewed.
Which methodology produces the most findings?v
Across our buyer corpus, grey-box and white-box engagements consistently produce 15-30% more high and critical findings than black-box on the same target. The lift comes mostly from business-logic flaws and authorisation issues that are hard to detect from outside but obvious in code. Vulnerability counts (low and informational) often appear similar across methodologies, but high-impact findings differ measurably.
When should I choose black-box?v
Black-box is the right choice when your goal is to validate external-attacker resilience or to satisfy a compliance auditor who wants attestation that an independent tester failed to break in. SOC 2 Type II evidence, ISO 27001 surveillance audits, and customer-due-diligence responses are usually well-served by black-box testing. It is also the right choice when source code sharing is genuinely impractical (acquired company, legacy codebase, contractor restriction).
When should I choose grey-box?v
Grey-box is the best findings-per-dollar choice for most modern applications. It costs 20-40% more than black-box but typically produces 15-30% more high-impact findings, and it surfaces categories of issue (broken authorisation, business-logic abuse) that black-box rarely reaches. For PCI DSS pentests, FedRAMP testing, and any application handling regulated data, grey-box is increasingly the expected default.
When should I choose white-box?v
White-box is justified for the most security-sensitive scopes: financial transaction engines, identity providers, healthcare data platforms, cryptographic implementations, and anything where a logic flaw could produce material harm. The 60-80% premium is meaningful, so white-box is rarely the right choice for general-purpose web applications. Reserve it for the small set of components where comprehensive code review pays back the cost.
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